If you have dealt with valving for any length of time, you've probably noticed Valve manufacturers are not overly creative with the terms and vernacular used in the business. Take for example, "bolted Bonnet Valves." The body is bolted to the Bonnet to maintain system integrity. For "pressure seal Valves," system pressure aids the sealing mechanism. For "stop/Check Valves," when the Valve stem is in the closed position, flow is mechanically stopped, but when in the open position, the disc is free to act to check a reversal of flow. This same principle applies to other terminology used for design, as well as Valve types and their component parts.